Automatic by-pass for pumps.



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AUTOMATIC BY-PASS FOR PUMPS.

APPLICATION rum) AUG. 10. 1909.

1,001,295. Patented Aug. 22, 1911.

2 SHEETS-BEBE! 2.

COLUMBIA PLANDGRAFN 0.. WASHINGTON, D- "1 ALBERT E. MOORHEAD, OF SAN FRANCISCO, CALIFORNIA.

AUTOMATIC BY-PASS FOR PUMPS.

Specification of Letters Patent.

Application filed August 10, 1909.

Patented Aug. 22, 1911.

Serial No. 512,184.

To all whom it may concern:

Be it known that I, ALnnn'r 15. Moon- HEAD, a citizen of the United States, l'cl-dtllng' at San Francisco, in the county of San Francisco and State of California, have invented new and useful Improvements in Automatic By-Passes for Pumps, of which the following is a specification.

The present invention relates to an automatically operating device, in the nature of a valved by-pass, adapted for use with air pumps acting to produce either suction or compression, the object of the invention being to provide means by which to economize in the power required to operate the pump under varying conditions of load.

In the accompanying drawings :--Figure 1 is a plan view of a pump cylinder provided with my improved by-pass valve mechanism. Fig. 2 is a longitudinal, vertical section of the same. Fig. 3 an enlarged cross-section of the VELlVO-IIlGll'lbBl', taken on the line 3-3 of Fig. 2.

Referring to the drawings, 1 indicates the main cylinder of an air pump, which may be adapted either for suction or compression, or, by the use of suitable valves, may be used for either purpose. The pump illustrated is adapted to act as a suction pump, the cylinder 1 having at each of its ends an outlet check-valve 2, and an inlet check valve 2. In said cylinder is a reciprocating piston or plunger. Passagesl-, l.lead 'lrom the ends of said cylinder to ports 5, 5, in a cylindric valve chamber formed in a valve casing (3. In said valve casing is a sliding valve member 7 having the form ot a hol low cylinder provided near its ends with ports 8 and 8', each of which preferably consists of an annularly arranged series oli openings. Said valve member 7 is attached to a valve rod 9, which passes through stutting boxes 10, 10 on the opposite end walls of the valve casing. To one end of said valve rod is connected a contractile coiled spring 11. The other end of said spring is connected with a hook 12 the shank of which is inserted through a yoke 14-, attached to the adjacent head or end wall of the valve casing. Said hook 12 is screwthreaded to receive a thumb-nut 13 adapted to bear against the outer face of the said yoke. By means of said hook and thumbnut, the tension of the spring may be varied as desired. The other end of the valve rod 9 is attached to a piston 15, which fits and slides in a regulating cylinder 16 arranged in axial alinemcnt with the valve member 7. From the outer end of said cylinder 16 a pipe 18 leads to a tank 25. Said pipe 18 is intended for use when the pump is a suction pump and said tank is subject to a partial vacuum. From the inner end of said cylinder 16 a pipe 17 leads to the same tank, said pipe 17 being designed for use when the pump is a compression pump and the tank is used as a reservoir or storage tank for compressed air. Suitable valves :26 and 27 are applied to said pipes to permit either of the same to be used, as desired. The pump illustrated is arranged to operate as a suction pump and the tank 25 is connected by a pipe 30 with a chamber 231, from which open the inlet check-valves 2, 2. In order to use the pump as a compression pump, reversely acting valves will be substituted for the check-valves 2 and 2 and the valves used in place oil the valves 2 will open inwardly, while those used in place 01" the valves 2 will open outwardly. Upon said valve rod 9 is secured an indicator arm 19, the outer end. of which slides or moves in a slot 20 formed in a part or casting 20 by which the regulating cylinder 16 is com ncctcd with the adjacent end of the valve casing 9. The edges of said part 20 at the sides of said slot are marked with indicating scales, that, 21, on one side 0f the slot indicating the degree of vacuum and that,22,on the other side of the slot the degree of air compression. An adjustable stop-member, pref erably having the form of a setscrew 2 :1, limits the movement of said indicator arm and therefore also of the valve-rod and valve member, in the direction in which said parts are moved by the action 01'' the spring 1.1.

The mode of operation is as follows: Supposing that the pump is used as a suction pump for operating vacuum cleansing appliances and that the capacity of the pump is (500 cubic feet of air a minute. Assuming that this capacity he sullicicnt for six men working in a building with six sue tion cl mnsing appliances, and that the tension of the spring is so adjusted as to maintain a degree of vacuum necessary for the proper operation of that number oi such cleansing appliances, so long as all six devices are in operation, the pump will act to draw from the tank (500 cubic feet or air per minute and all of the air so drawn from the tank will be expelled into the atmosphere through one of the check-valves 2, 2. But if three of the men were to stop working and close the pipes leading from their appliances to the tank, then the pump would continue to draw in 600' cubic feet per minute, and, because this air will be drawn through only three of the devices instead of six, the degree of vacuum within the tank will be increased correspondingly; the efiect being to produce a higher degree of vacuum at each device than is required for its proper operation, besides requiring the engine to do the same work as before, although only three devices be working. The by-pass valve device made as described, obviates these objectionable conditions, because the increased vacuum in the tank produces a corresponding increased vacuum in the regulating cylinder 16, which has the eiiect of drawing the piston 15 outwardly in said cylinder, against the tension of the spring 10, and thereby moves the valve member 7 in a direction to bring the ports 8, 8 there of opposite the cylinder ports 5, 5, thereby establishing connection, through the interior of the hollow valve member, between said ports 5, and 5. When the valve member is so moved, therefore, all of the air will not be delivered to the atmosphere from the end of the pump cylinder toward which the pistonis moving, but .apart of such air will pass by the ports 5 and 8 and through said hollow valve, and then through the ports 8, 5, into the opposite end of the cylinder, so that a correspondingly less quantity of air will be drawn into such opposite end or the cylinder and the quantity of air escaping to the atmosphere will equal the amount drawn in through the three appliances still working. Since the pump piston will not then operate against the increased vacuum due to the lessened number of appliances in use, the force required to reciprocate said piston will be correspondingly reduced and an equivalent saving of power will result.

The maximum amount of air which will be drawn from the tank by the pump may be regulated by the adjustable stop member or set-screw 23. If it be desired that such maximum amount shall be less than the full capacity of the pump, said stop member will be adjusted inwardly to a position in which it will prevent the valve from being moved by the spring a sufficient distance to fully close the ports 5, 5. When the stop member is so adjusted, air will constantly flow from one end of the pump cylinder to the other through said ports and the valve. Said stop member may be adjusted inwardly to a greater or less extent, according to the quantity of air required to be drawn from the tank. Thus, supposing that the engineer of the building knows that four men,

at the most, will be working at any time, he can set the set-screw so as to prevent more air being withdrawn from the tank than required to maintain in said tank the degree .of vacuum required for the proper operation of the tour appliances. If, at that time, one or more of the vacuum cleansing appliances should stop working, then the bypass device will automatically adjust itself to the changed conditions and lessen the power required to operate the pump.

In case the pump be used for compression, the valve in the pipe 18 is closed and that in the pipe 17 is opened. Air will then be admitted under pressure to the inner side of the piston 15 and will move the same against the tension of the spring, in the same direction in which it is moved by suction, when the pump is operating as an exhaust pump, with like results in regulation and economy of power.

1 claim as my invention 1. The combination of a pump cylinder, a valve casing provided with two ports severally communicating with the opposite ends of the pump cylinder, a sliding valve member in said casing, adapted to move over said ports and arranged when in one position to close said ports and when in another position to connect said ports with each other, a regulating cylinder in communication at one of its ends with the pump cylinder, a piston in said regulating cylinder, said piston being connected and moving with said valve member, and a spring acting on said valve member in opposition to the pressure on the said piston.

'2. The combination of a pump cylinder, a valve casing provided with two ports severally communicating with the ends of the pump cylinder, a sliding valve member therein, adapted to move over said ports and arranged in one position to close said ports and in another position to provide communication between the same, a regulating cylinder, one end of which is in communication with the pump cylinder, a piston in said regulating cylinder, a piston rod attached to said piston and connected with said valve, and a spring acting on said valve rod in opposition to the pressure on said piston.

3. The combination of a pump cylinder, a valve casing provided with a cylindric valve chamber and with two ports severally communicating with the ends of the pump cylinder, a hollow, cy1indric,-endwise sliding valve member therein adapted to move over said ports, and arranged in one position to close said ports and in another position to provide communication between them, a regulating cylinder, one end of which is in communication with said pump cylinder, a piston in said regulating cylinder connected and moving with the said valve member, a

spring acting on the valve in opposition to the pressure on the piston, and means for varying the tension of said spring.

l. The combination of a pump cylinder,

a valve casing provided with two ports severally communicating with the ends of the pump cylinder, a sliding valve member in said valve casing adapted to move over said ports and arranged in one position to close said ports and in another position to provide communication between the same, a regulating cylinder, one end of which is in comma nication with the pump cylinder, a piston in said regulating cylinder, a piston rod attached to one end of said valve member and extending through both ends of the valve casing, one end of said rod extending into the regulating cylinder and being attached to the said piston, and a spring attached to the opposite end of said valve rod.

5. The combination of a pump cylinder, a valve casing provided with two ports severally communicating with the ends of said pump cylinder, a sliding valve member in said casing adapted to move over said ports and arranged in one position to close said ports and in another position to provide communication between them, a tank in communication with said pump cylinder, a reg ulating cylinder, a piston in said regulating cylinder connected and moving with said valve member, a spring acting in the valve member in opposition to the pressure on said piston, and a pipe connecting one end of said regulating cylinder with the said tank.

(3. The combination of a pump cylinder, a valve casing provided with two ports severally in communication with the ends of said pump cylinder, a sliding Valve member in said casing adapted to move over said ports and arranged in one position to close said ports and in another position to provide communication between the same, a regulating cylinder, a piston therein connected and moving with said valve, pipes connected with the opposite ends of said regulating cylinder, said pipes connnunicating with the pump cylinder, and valves for closing said pipes, whereby said regulating cylinder may be used either for pressure or vacuum.

7. The combination of a pump cylinder, a valve casing provided with two ports severally in connnunication with the ends of said pump cylinder, a sliding valve member in said casing adapted to move over said ports and arranged in one position to close said ports and in another position to provide communication between the same, a regulating cylinder in communication at one end with the pump cylinder, a piston in said regulating cylinder, a piston rod attached to said piston and connected with said valve, a spring acting in the valve member in opposition to the pressure on the said piston, and adjustable means limiting the movement of said valve member under the action of said spring.

8. The combination of a pump cylinder, a valve casing provided with two ports severally communicating with the ends of said pump cylinder, a sliding valve member in said casing adapted to move over said ports and arranged in one position to close said ports and in another position to provide comnuinication between the same, a regulating cylinder in comnninication at one of its ends with the pump cylinder, a piston in said regulating cylinder connected and moving with said valve, an indicator connected and moving with said valve and an indicating scale along which said indicator moves.

.ln.testi1 nony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

ALBERT F. MOORHEAD.

Witnesses FRANCIS M. lVnron'r, 1). B. Rioimims.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

